The invention relates to an improved device for making electrical connections between a plurality of conductors, which reliably grips and isolates the ends of the conductors, allows the connection of a single pair of conductors and simplifies the operation of accomplishing electrical connections without the aid of extraneous tools; and, particularly, relates to connections between telephone lines at a network interface unit.
At present, a wide variety of conductor splicing electrical connectors are used in telephone systems. Generally, these connectors comprise at least two separate and distinct elements, is namely, an index strip and a connector module. U.S. Pat. No. 3,798,587 to B. C. Ellis, Jr. et al. (xe2x80x9c""587 patentxe2x80x9d) discloses one such typical wire connecting blacks, wherein the index strip has a plurality of teeth of alternating height which are spaced-apart, and the connector module has a plurality of slotted insulation displacement connectors and a plurality of teeth of alternating height and spaced-apart, identical to those of the index strip. The ""587 patent discloses electrical connections between two sets of conductors are accomplished by first placing the first set of conductors along slots between the spaced-apart teeth of the index strip and the second set of conductors between slots of the insulation displacement connectors of the spaced-apart teeth of the connector module. Then the connector module is placed over the index strip, with the slotted insulation displacement connectors making electrical connection between the first and second set of conductors by penetrating the insulation.
U.S. Pat. No. 4,118,095 to R. N. Berglund et al. (xe2x80x9c""095 patentxe2x80x9d) discloses an improved two-element wire connecting block. Significantly, the ""095 patent modifies the connector module disclosed in the ""587 patent to facilitate alignment of the slotted insulation displacement connectors and to provide an integral skirt for maintaining electrical isolation of the end of the first set of conductors to minimize short circuits between conductors.
Further improvement of the two-element system is the addition of a third element, a cap module, as disclosed in U.S. Pat. No. 3,772,635 to D. R. Frey et al. (xe2x80x9c""635 patentxe2x80x9d) and U.S. Pat. No. 4,262,985 to A. A. Muehlhausen II (xe2x80x9c""985 patentxe2x80x9d). The ""635 patent discloses a cap module, for use with a modified index strip and a modified connector block, which serves the purpose of snubbing the second set of conductor ends. The ""985 patent discloses a cap module capable of gripping, snubbing and isolating the second set of conductor ends. The cap module of both the ""635 and the ""985 patents are snap-mounted onto the connector module with a latch-hole interlocking mechanism.
Normally the assembly of the wire connecting blocks disclosed in these patents require an expensive tool such as that disclosed in the ""635 patent and U.S. Pat. No. 3,898,724 to T. A. Conorich (xe2x80x9c""724 patentxe2x80x9d). The seating tool is used to trim and properly snub the conductors into slots between the spaced-apart teeth of the wire connecting blocks to achieve electrical connections.
U.S. Pat. Nos. 3,772,635, 3,798,587, 3,898,724, 4,118,095 and 4,262,985 discussed above are hereby incorporated by reference as background of the invention.
Prior art wire connecting blocks described above are suitable for installation and for rearrangement of a large-scale telephone system because typical connector modules and seating tools are designed to make multiple pairs of electrical connections at one time. Once a telephone system had been properly installed and all electrical conductors pre-connected, rearrangement of a large-scale network interface unit require a visit from a skilled telephone service technician, who can work through the complex maze of telephone connections and is likely to possess an expensive seating tool for making efficient and effective connections. Rearrangement of a large-scale network interface unit justifies a visit from a telephone service technician or the purchase of a seating tool, which can be time consuming and costly.
When rearrangement of a network interface unit involves only a few electrical connections, it does not justify the cost of purchasing an expensive seating tool or requiring a visit from a telephone service technician. However, with prior art wire connecting blocks, such a task cannot be effectively accomplished without the assistance of a seating tool or a telephone service technician, adding materially to the cost and time expended.
In order to rearrange electrical connections of a telephone system, it is necessary to first trace the telephone connections to the connector module located in the network interface unit, disassemble the electrical connections from the slots of the connector module and then reassemble the electrical connections at slots corresponding to the desired connections on the index strip.
Prior art wire connecting blocks contain a number of shortcomings when handled by an inexperienced person. For example, the two-element prior art wire connecting block does not provide a reliable positive grip of the electrical conductors to allow secure tracing of the wires. The two-element wire connecting block also provides minimum to no electrical isolation of the conductor ends. Furthermore, proper use of the two-element wire connecting block requires an expensive seating tool. On the other hand, while a three-element prior art wire connecting block eliminates some of these drawbacks, it requires the removal of the cap module before the removal of the electrical connections from the connector module. Such a cap module is generally snap mounted onto the connector module by way of a spring-latch-hole interlocking feature, making its removal difficult. Even if removal of the cap module is successful, it can be easily lost or misplaced.
It is therefore the aim of this invention to provide an improved connector module of a wire connecting block that facilitates the rearrangement of electrical connections in a simple, positive manner, even by unskilled persons.
The invention provides an improved device for making electrical connections between conductors. The invention improves upon a two-element prior art wire connecting block to achieve benefits of and beyond a three-element prior art wire connecting block.
The invention provides an integrated push cap that facilitates rearrangement of electrical connections without the assistance of a service technician. The integrated push cap also serves to snub electrical conductors into slotted insulation displacement connectors, thereby eliminating the need of a specialized seating tool.
The invention further provides isolation of the ends of the electrical conductors to minimize short circuits between conductors in an outdoor environment. The invention also provides strain relief on the electrical conductors at the point of contact with the slotted insulation displacement connectors.
The invention provides reliable gripping of electrical conductors to allow secure tracing of wires to the wire connecting block.
The invention, when used for telephone wire connections, contemplates an improved connector module for use in conjunction with existing prior art index strip, such as those described in U.S. Pat. Nos. 3,798,587 and 4,118,095. The improved connector module of this invention has a plurality of alternating height, spaced-apart, teeth and a plurality of slotted insulation displacement connectors, such as shown in existing prior art connector modules. The improved connector module also has an integrated push cap, pivotable from an open to closed positions. In the closed position, the push cap is designed to fit over a predetermined sequence of alternating height, spaced-apart, teeth. A protuberance-recess locking mechanism is provided to keep the push cap in a closed position, yet allows repetitive opening and closing of the push cap. The push cap has a pair of notched ribs on the bottom surface for snubbing and seating a pair of electrical conductors in the slotted insulation displacement connectors.
Housed within the improved connector module are one or more pairs of openings, such as cylindrical chambers, designed to fit different gauge wires, such as a 22 or 26 gauge wire. The chambers are positioned in alignment with the slots between the teeth. The ends of electrical conductors are inserted into the mating chambers while the push cap is in an open position, with the body of the electrical conductors resting in the spaces between the alternating height teeth in position for snubbing and seating into the insulation displacement connectors. Upon closing the push cap, the electrical conductors are seated in the slotted insulation displacement connectors, with the ends of the conductors displaced at an angle, forming the letter xe2x80x9cL.xe2x80x9d The chambers effectively isolate the ends of the conductors. The L-shaped conductors serve as strain relieve at the point of contact with the slotted insulation displacement connectors. Furthermore, in combination with the protuberance-recess locking mechanism, the angle created along the conductors securely grip the conductors.